During the past eight years, the Yerkes National Primate Research Center (YNPRC) has established, maintained, and expanded Specific Pathogen Free (SPF) colonies of both rhesus monkeys and pigtailed monkeys producing a total colony of 422 SPF monkeys. The central objective of the present project is to breed SPF macaque monkeys (chiefly rhesus monkeys of Indian ancestry) that are specific pathogen free (SPF) and genetically characterized - as defined by the National Center for Research Resources in RFA RR- 02-005 - specifically to provide subjects to NIH supported investigators for AIDS related research and thus to contribute to national health priorities. This objective will be achieved at the YNPRC initially utilizing the existing colony of 422 SPF macaque monkeys (331 rhesus monkeys of Indian ancestry; 91 pigtailed monkeys). Specifically, the existing SPF rhesus of Indian ancestry and pigtailed colonies will be increased via breeding (with over 100 births in these SPF groups in 2001), recruitment of young animals from YNPRC non-SPF breeding colonies via appropriate testing and separation, and by addition of a small (N=50) group of rhesus monkeys of Chinese origin in recognition of the increasing use of this subtype in some AIDS investigations. An innovative aspect of the project will include a research effort designed to enhance the value of the resource by developing a program in Assisted Reproductive Techniques to support the SPF program and to provide for genetically defined animals. The overall aim of the project is to provide all the trained personnel and resources that are necessary to maintain and enlarge SPF breeding groups and to manage them in order to optimize health and reproductive performance in support of national health related priorities established by NIH and NCRR. The YNPRC will work closely with NCRR and the Coordinating Committee they have established in implementing recommendations regarding uniform husbandry procedures, standarization of screening tests and such other matters as the committee may decide. The YNPRC also will work in coordination with other facilities maintaining NCRR supported SPF colonies and with any investigators identified by NCRR to maximize the potential that national priorities for SPF production will be attained.